NWC report boosts Australian brackish desalination

Brackish groundwater desalination can be considered a viable community water supply option in some areas, says a report just announced by Australia’s National Water Commission (NWC).

Brackish groundwater: a viable community water supply option? Waterlines report No 66 (December 2011) says that Australians rely heavily on groundwater sources, with around 4 million people dependent partially or totally on groundwater for domestic water supply.

However, in many cases, the concentration of dissolved salts is so high that the water is unsuitable for drinking without treatment.

The NWC report looks at the feasibility of treating brackish groundwater as a community water supply option in regional and remote communities in Australia. It seeks to provide water supply authorities with a practical way of determining what needs to be taken into consideration for a new water-supply investment in groundwater.

The report presents six case studies on sites around Australia where desalination technology has already been implemented. Its key findings indicate:

Brackish water desalination using reverse-osmosis membranes has been successfully employed since the 1980s to produce drinking water in a number of inland towns and communities where other water-supply options have been limited

Investment in detailed preliminary investigations was a key factor in the success and viability of the long-term operation of the case-study sites

Capital and operating costs for desalination are location-specific and can vary greatly between installations

Brine-disposal management poses significant environmental and cost challenges for water managers, with evaporation ponds requiring up to 50% of the capital costs

Beneficial reuse of brine for agricultural purposes is not common in Australia; however this report identifies some salt-tolerant crop varieties which could be considered for Australian applications.

The overall feasibility of new groundwater supplies is dependent on a number of considerations, particularly geographic location and raw water quality. Subject to these considerations, brackish groundwater desalination can be considered a viable community water supply option in some areas, the report concludes.